Implantable pulse generators (IPGs) are commonly used to treat irregular heartbeats, known as arrhythmias. Cardiac pacemakers, for example, are designed to manage bradycardia, an abnormally slow or irregular heartbeat. Left untreated, bradycardia can cause symptoms such as fatigue, dizziness, and fainting. Cardiac resynchronizers are a particular class of pacemaker that provide cardiac resynchronization therapy, such a bi-ventricular pacing, for patients suffering from heart failure. Implantable cardioverter defibrillators (ICDs), by way of further example, are designed to treat tachycardia, heart rhythms that are abnormally fast and life threatening. Some forms of tachycardia can result in sudden cardiac death, if left untreated. The IPG 110 illustrated in FIG. 1, shown coupled to a heart 120, is one example of a variety of patient implantable medical devices (PIMD) used to gather data and/or deliver a therapy, such as a cardiac therapy.
PIMD's are increasingly being equipped with an on-board, volatile memory in which telemetered signals can be stored for later retrieval and analysis. The telemetered signals provide various types of patient device information, such as atrial electrical activity, ventricular electrical activity, time of day, activity level, cardiac output, oxygen level, cardiovascular pressure measures, pulmonary measures, and any interventions made on a per heartbeat or binned average basis. In addition, a growing class of cardiac medical devices, including implantable heart failure monitors, implantable event monitors, cardiovascular monitors, and therapy devices, are being used to provide similar stored device information. These devices are typically designed to store approximately thirty minutes of heartbeat data. Telemetered signals are also stored in a broader class of monitors and therapeutic PIMD's for other areas of medicine, including metabolism, endocrinology, hematology, neurology, muscular, gastrointestinal, genital-urology, ocular, auditory, and the like.
Information stored in a PIMD is typically retrieved using a proprietary interrogator or programmer, often during a clinic visit or following a device event. The volume of data retrieved from a single device interrogation procedure can be large and proper interpretation and analysis can require significant physician time and detailed subspecialty knowledge, particularly by cardiologists and cardiac electrophysiologists. Present approaches to data interpretation and understanding, and practical limitations on time and physician availability, make such analyses impracticable.
Conventional systems for collecting and analyzing pacemaker and ICD telemetered signals in a clinical or office setting can be used to retrieve data, such as patient electrocardiogram and any measured physiological conditions, collected by the IPG for recordation, display, and printing. The retrieved data may be displayed in chronological order and analyzed by a physician. Conventional systems often lack remote communications facilities and must be operated with the patient present. These systems present a limited analysis of the collected data based on a single device interrogation and lack the capability to recognize trends in the data spanning multiple episodes over time or relative to a disease specific peer group.